SPOT 5与HJ遥感影像用于冬小麦氮素监测的效果对比

为探讨HJ遥感影像对冬小麦氮素监测的适用性，利用同期获取的SPOT5和HJ1B遥感影像，结合同步地面取样测试，从传感器的光谱响应、监测模型精度以及叶片氮含量空间填图3个方面，对冬小麦氮素的遥感影像监测效果进行了分析与评价。结果表明，两类遥感影像的3个波段反射率及植被指数与小麦叶片氮含量均密切相关，其中，SPOT5影像的最优模型植被指数为GNDVI（绿色归一化植被指数），HJ1B影像的最优模型植被指数为NDVI（归一化植被指数），SPOT5影像在监测精度上优于HJ1B影像，但差别不大。填图结果表明，除地块较破碎地带外，利用HJ1B影像反演填图所得的小麦叶片氮含量在空间分布上与SPOT5影像结果比较一致。说明利用SPOT5与HJ遥感影像监测小麦氮素营养状况都是可行的，而HJ遥感影像在一定精度要求范围内能够替代SPOT5等遥感影像的监测效果。

Comparative Analysis of Monitoring Winter Wheat Nitrogen with SPOT 5 and HJ Image

Aimed to assess the capability of HJ images in monitoring of winter wheat leaf nitrogen concentration, the field investigation was carried out, which exactly corresponded with the acquiring timing of a scene of SPOT 5 image and a scene of HJ 1B Image. The performance of SPOT 5 and HJ 1B images was evaluated in terms of the spectral response of sensors, the accuracy of monitoring model as well as the spatial distribution pattern of predicted leaf nitrogen concentration. The results showed that wheat leaf nitrogen content had good correlation with the different wavebands reflectance and vegetation indices of SPOT 5 and HJ 1B. GNDVI and NDVI derived from SPOT 5 and HJ 1B were two better parameters, respectively. SPOT 5 image provides a much better accuracy in monitoring wheat leaf nitrogen concentration than HJ 1B image. Except in some fragmental field area, they had a highly consistent spatial distribution pattern of winter wheat leaf nitrogen concentration. Study results indicated that both SPOT 5 and HJ images could be used to monitor wheat nitrogen status. Moreover, HJ image can be used to replace SPOT 5 image as remote sensing data sources in some accurate range.